Various fluorinated polymer compositions are known to be useful as treating agents to provide surface effects to substrates. Surface effects include repellency, soil resistance, soil release, stain resistance and stain release, and other effects, which are particularly useful for fibrous substrates and other substrates such as hard surfaces. Many such treating agents are fluorinated polymers or copolymers.
Most commercially available fluorinated polymers useful as treating agents for imparting repellency to substrates contain predominantly more than eight carbons in the perfluoroalkyl chain to provide the desired properties. Honda et al, in Macromolecules (2005), 38(13), 5699-5705, teach that for perfluoroalkyl chains of greater than 8 carbons, orientation of the perfluoroalkyl chains is maintained in a parallel configuration while for such fluoroalkyl chains having fewer carbons, reorientation occurs. Thus short fluoroalkyl groups having 6 or less carbons have traditionally not been successful commercially for imparting surface effects to substrates because of the absence of highly ordered perfluoroalkyl chains at the outermost surfaces.
U.S. Pat. No. 6,833,419 discloses a water-soluble or water-swellable copolymer obtained by free-radical copolymerization of acryloyldimethyltaurine and/or acryloyldimethyltaurates with one or more fluorine-containing compounds. The resulting copolymers are useful as thickeners. However, no surface effects to substrates are disclosed in this patent.
There is a need for a method of treating substrates with water-soluble polymer compositions which impart surface effects including water repellency, oil repellency, soil resistance, soil release, stain resistance and stain release, and other effects, while using fluorinated monomers containing perfluoroalkyl groups of eight carbons or less. The present invention provides such a method.